Medical stand apparatus

ABSTRACT

A medical stand apparatus supports light-weight medical equipment and is installable directly on a patient bed or in a small space adjacent to a patient bed.  
     The medical stand apparatus has a base ( 10 ) spaced away from the floor (F), a horizontal rotation member ( 11 ), and a protrusion ( 11   a ). With the use of these elements, the medical stand apparatus directly attaches a parallel link mechanism ( 6 ) including a longitudinal sub-link ( 14 ) and a lateral sub-link ( 15 ) to support the medical equipment to a table ( 8 ) on which a patient ( 7 ) is laid.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a medical stand apparatus.

[0003] 2. Description of the Related Art

[0004] A medical field such as neurosurgery employs a surgicalmicroscope to enlarge and observe a target part and carry out anoperation on the target part. The surgical microscope must be easy touse, to shorten an operation time and relieve a patient and an operatorof physical and mental fatigue.

[0005] The surgical microscope or any other medical equipment isfrequently combined with assistant apparatuses for easing the use of themedical equipment. Among the assistant apparatuses, a stand apparatus isused to support the medical equipment. An example of a stand apparatusis disclosed in Japanese Unexamined Patent Publication No. 6-197912. Thestand apparatus usually has a parallel link mechanism and acounterweight, to lightly move and stop a heavy surgical microscope atan optional spatial position. With the stand apparatus, an operator mayquickly and easily move the surgical microscope like the operator's ownlimbs to a desired position without assist of actuator, keep themicroscope at the position, and orient the microscope toward a targetpart.

SUMMARY OF THE INVENTION

[0006] Conventional stand apparatuses are designed to support large andheavy surgical microscopes and attachments, and therefore, arethemselves large and heavy. Accordingly, they are improper to supportlight medical equipment such as photon radiation systems, endoscopes, ormeasuring devices. Namely, the conventional stand apparatuses are toobulky to support light medical equipment and are inconvenient totransport and handle.

[0007] When a surgical microscope supported by a conventional standapparatus is moved, a counterweight of the stand apparatus widely shiftsits position. The stand apparatus, therefore, needs a large installationspace and is unable to install in a narrow space beside a bed, ordirectly to the bed.

[0008] An object of the present invention is to provide a medical standapparatus that is appropriate to support light medical equipment and isdirectly installable on a bed or in a narrow space beside a bed.

[0009] In order to accomplish the object, a first aspect of the presentinvention provides a medical stand apparatus 1 having a base 11 fixed toa patient table 8 at a position away from the floor F, a horizontallyrotatable member attached to the base and horizontally rotatable arounda vertical axis α1 orthogonal to the base, a parallel link mechanism 6supported by a fulcrum S arranged on the horizontally rotatable member,the link mechanism having a pair of parallel longitudinal links (2,3)and a pair of lateral links (4,5), a support arm 4 a extending from theupper lateral link 4 of the link mechanism, to support medical equipmentM at a front end thereof, and a counterweight W opposite the medicalequipment across the fulcrum, to cancel weight acting in an incliningdirection of the link mechanism around the fulcrum S and keep themedical equipment at a spatial position. The front end of the supportarm 4 a is provided with an end link 12. The link mechanism has aconnecting shaft β1 serving as a start point of the support arm 4 a. Tothis connecting shaft, a crank 13 is fitted. The crank 13 is connectedto a longitudinal sub-link 14 extending in parallel with thelongitudinal links and is also connected to a lateral sub-link 15extending in parallel with the support arm 4 a. A lower end of thelongitudinal sub-link 14 is articulated at a horizontal protrusion 11 aformed on the horizontally rotatable member. An end of the lateralsub-link 15 opposite the crank is articulated at an upper end β9 of theend link, so that the end link may always maintain a given posture. Alower end of the end link 12 supports the medical equipment M.

[0010] In other words, the first aspect of the present inventionprovides an assist-less medical stand apparatus 1 for manipulating amedical equipment M used for a patient 7 on a patient table 8 having afirst parallel linkage 6 for weight balancing of the apparatus, a secondparallel linkage, and a third parallel linkage to cooperatively movewith the second parallel linkage for holding the medical equipment andmaintaining a posture thereof. The first parallel linkage has a firstarticulating element β1, a second articulating element β4, a thirdarticulating element β3, and a fourth articulating element β2. Where thefirst articulating element and the second articulating element arelinked by a first linkage 2, the second articulating element and thethird articulating element are linked by a second linkage 5, the thirdarticulating element and the fourth articulating element are linked by athird linkage 3, the fourth articulating element and the firstarticulating element are linked by a fourth linkage 4, the thirdarticulating element supports a counterweight, the first linkage 6 isarticulated by a fifth articulating element S on a supporting member(10,11), and the supporting member fixes the apparatus with respect tothe patient table 8. A second parallel linkage has a sixth articulatingelement S, a seventh articulating element β8, a eighth articulatingelement β6, and a ninth articulating element β1. Wherein the sixtharticulating element S and the seventh articulating element β8 arelinked by a sixth linkage 11 a, the seventh articulating element β8 andthe eighth articulating element β6 are linked by a seventh linkage 14,the eighth articulating element β6 and the ninth articulating element β1are linked by a eighth linkage 13, the ninth articulating element β1 andthe sixth articulating element S are linked by a fifth linkage 2, thesixth linkage is fixed with respect to the supporting member (10,11),and the fifth linkage and the first linkage are fixed each other. Athird parallel linkage has a tenth articulating element β1, a eleventharticulating element β7, a twelfth articulating element β9, and athirteenth articulating element β5. Wherein the tenth articulatingelement β1 and the eleventh articulating element β7 are linked by aninth linkage 13, the eleventh articulating element β7 and the twelftharticulating element β9 are linked by a tenth linkage 15, the twelftharticulating element β9 and the thirteenth articulating element β5 arelinked by a eleventh linkage 12, the thirteenth articulating element β5and the tenth articulating element β1 are linked by a twelfth linkage 4a, the thirteenth articulating element β5 are fixed by the fourthlinkage 4, the tenth articulating element, the ninth articulatingelement, and the first articulating element are fixed each other, andthe eleventh articulating element β7 and the eighth articulating elementβ6 are linked by a thirteenth linkage 13.

[0011] A second aspect of the present invention provides a medical standapparatus 18 having a base (19,20) set on the floor F, a post 21installed on the base being horizontally articulated about an axis ofrotation α1 oriented in a predetermined direction with respect to thebase, upper and lower articulations (S1, S2) being provided by the post,a parallel link mechanism 6 supported by the upper articulation S1 andhaving a pair of parallel longitudinal links (2, 3) and a pair oflateral links (3, 4), a support arm 4 a extending from the upper laterallink 4 of the parallel link mechanism, and an end link 12 beingsupported by a front end of the support arm 4 a. The apparatus 18 alsohas a crank 13 articulated about a first articulation β1 of the parallellink mechanism 6, a longitudinal sub-link 14 parallel with thelongitudinal links (2, 3), a lower end of the longitudinal sub-link 14being articulated by an articulation β8 at a front end of a horizontalfirst upper protrusion 30 formed on the post, wherein one of thelongitudinal links 13 adjacent to the support arm 4 a, the crank 13, thelongitudinal sub-link 14, and the first upper protrusion 30 form a firstauxiliary parallel link. The apparatus 18 further has a lateral sub-link15 parallel with the support arm 4 a, the lateral sub-link 15cooperatively moving in response to position of the longitudinalsub-link 14 through the crank 13, an upper end of the end link beingarticulated by an articulation β9 at a first end of the lateral sub-linkopposite the crank, wherein the support arm 4 a, the upper end of theend link 12, the lateral sub-link 15, and the crank 13 form a secondauxiliary parallel link. The apparatus 18 also has an interlockedlongitudinal link 22 always parallel with the longitudinal links (2, 3),an upper end of the interlocked longitudinal link being articulated atthe lower articulation S2, a lower end of the interlocked longitudinallink being articulated at a first end of an interlocked lateral linkβ14, a second upper protrusion 2 a formed at a lower end of thelongitudinal links, a front end of the second upper protrusion beingconnected to a front end of a lower protrusion 22 a formed at an upperend of the interlocked longitudinal link through an interlockedlongitudinal sub-link 24, wherein the orientation and length of astraight line between the upper end and lower articulations (β12, β13)of the interlocked longitudinal sub-link 24 are equal to those of astraight line between the upper and lower articulations (S1, S2).Furthermore the apparatus 18 has a weight link 25 connecting an end ofthe lower lateral link 5 of the parallel link mechanism opposite themedical equipment and a second end of the interlocked lateral link 23,the weight link 25 being parallel with a straight line L2 between theupper articulation S1 and the first end of the interlocked lateral linkβ14, a counterweight W arranged at the second end of the interlockedlateral link β15, wherein the counterweight cooperatively moves towardand away from the lower articulation S2 in response to movement of themedical equipment M about the upper articulation S1, and the weight ofthe counterweight acts on the parallel link mechanism 6 to keep themedical equipment at an optional spatial position.

[0012] A third aspect of the present invention offsets the lower fulcrumS2 of the second aspect from just below the upper fulcrum S1 toward themedical equipment M side.

[0013] A fourth aspect of the present invention provides the end link ofany one of the first and second aspects with a first rotation shaft β10to support a rotary arm 16, and provides the rotary arm with a secondrotation shaft β11 orthogonal to the first rotation shaft β10. A holder17 to hold the medical equipment M is journaled on the second rotationshaft β11. An intersection A of the first and second rotation shafts isset to agree with the gravitational center of the medical equipment M sothat the posture of the medical equipment may freely be set. Namely, therotary arm and holder (16, 17) support the medical equipment so that themedical equipment may freely change its posture. This helps an operatoreasily and finely adjust the position and posture of the medicalequipment.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a front view showing a medical stand apparatus accordingto a first embodiment of the present invention;

[0015]FIG. 2 is a perspective view showing a medical equipmentsupporting part of the apparatus of FIG. 1;

[0016]FIG. 3 is a perspective view showing an installation part of theapparatus of FIG. 1;

[0017]FIG. 4 is a schematic view showing a raised state of a support armextending from a parallel link mechanism of the apparatus of FIG. 1;

[0018]FIG. 5 is a schematic view showing a lowered state of the supportarm;

[0019]FIG. 6 is a schematic view showing a support arm lowered statewith longitudinal links of the link mechanism being inclined to oneside;

[0020]FIG. 7 is a schematic view showing a support arm raised state withthe longitudinal links being inclined to the other side;

[0021]FIG. 8 is a perspective view showing an endoscope supported by thestand apparatus;

[0022]FIG. 9 is a front view showing a medical stand apparatus accordingto a second embodiment of the present invention in a state that mainaxes of a link 2 and a post 21 are substantially agree with each other;

[0023]FIG. 10 is a front view showing an inclined state of a parallellink mechanism of the apparatus of FIG. 9; and

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0024] Embodiments of the present invention will be explained withreference to the accompanying drawings.

[0025] Through the drawings, each shaft or articulation is representedwith a dot-and-dash center line that corresponds to an axis of rotationthereof.

First Embodiment

[0026] FIGS. 1 to 8 show a medical stand apparatus according to thefirst embodiment of the present invention. The stand apparatus 1 has anarticulation S around a principal axis of rotation supporting a parallellink mechanism 6. The link mechanism 6 has a pair of parallellongitudinal links 2 and 3 and a pair of lateral links 4 and 5. Thelateral link 4 is extended to form a support arm 4 a. A front end of thesupport arm 4 a supports medical equipment M. A counterweight W isprovided to cancel weight acting in an inclining direction of the linkmechanism 6 around the articulation S and hold the medical equipment Mat any spatial position.

[0027] The stand apparatus 1 is fitted to a horizontal table 8 on whicha patient 7 is laid. The stand apparatus 1 has a base 10 as a supportmember provided with a fitting unit 9. The fitting unit 9 has achannel-shaped side face and is fitted to an edge of the table 8 awayfrom the floor F. The base 10 has an articulation portion α1 around aprincipal axis of rotation being substantially orthogonal to thehorizontal table 8. A horizontally rotatable member 11 is attached tothe base 10. The rotatable member 11 is horizontally articulated about aprincipal axis of rotation α1. The articulation α1 is provided with anelectromagnetic clutch Cl to lock the rotation of the rotatable member11. On the rotatable member 11, the articulation S of the link mechanism6 is arranged. A principal axis of the articulation S is substantiallyorthogonal to that of the articulation α1. The articulation S isprovided with an electromagnetic clutch C2 (FIGS. 1 and 3) to lock therotation of the link mechanism 6 around the articulation S.

[0028] The parallel link mechanism 6 is formed by connecting thelongitudinal links 2 and 3 and the lateral links 4 and 5 to each otherat their ends through connecting articulations β1, β2, β3, and β4. Inother words, a first parallel linkage for weight balancing of theapparatus 1 is formed by comprising the articulations β1, β2, β3, andβ4. The articulation β4 between the links 2 and 5 is provided with anelectromagnetic clutch C3 to lock the deformation of the link mechanism6 in an inclining direction around the articulation β4. The articulationβ3 between the links 3 and 5 is provided with the counterweight W. Theparallel link mechanism 6 realizes weight balance about the articulationS.

[0029] The upper lateral link 4 of the link mechanism 6 is extended toform the support arm 4 a. A front end of the support arm 4 a has an endlink 12 which is rotatable around a connecting articulation β5. Thesupport arm 4 a is curved upwardly so that it may not interfere with thehead of an operator.

[0030] The support arm 4 a has a start point on the articulation β1 thatsupports an L-shaped crank 13. The crank 13 has a horizontalarticulation β6 that is on the same horizontal line on which thearticulation β1 is present. The crank 13 also has a verticalarticulation β7 that is on the same vertical line on which the shaft β1is present. The articulation β6 is connected to an articulation β8through a longitudinal sub-link 14. The articulation β8 is arranged at afront end of a horizontal protrusion 11 a protruding from the rotatablemember 11. The sub-link 14 is parallel with the link 2 and has a lengthequal to an axial distance between the articulation S and thearticulation β1. In other words, a second parallel linkage is formed bycomprising the articulations β1, S, β8, and β6. The articulation β7 ofthe crank 13 is connected to an articulation β9 arranged at an upper endof the end link 12 through a lateral sub-link 15. The sub-link 15 isparallel with a straight line between the articulations β1 and β5 andhas a length equal to an axial distance between the articulations β1 andβ5. In other words, a third parallel linkage to cooperatively move withthe second parallel linkage is formed by comprising the articulationsβ1, β7, β9, and β5.

[0031] As a result, the articulations S, β1, β6, and β8 form anauxiliary parallel link mechanism. And the articulations β1, β5, β9, andβ7 form another auxiliary parallel link mechanism. These two parallellink mechanisms of the first and the second parallel linkage are linkedby a linkage formed by the crank 13.

[0032] In FIG. 2, a lower end of the end link 12 has an articulationβ10. On the articulation β10, one end of an L-shaped rotary arm 16 isarticulated. The rotary arm 16 has another articulation β11 at anotherend thereof. A principal axis of the articulation β11 is substantiallyorthogonal to that of the articulation β10. A holder 17 for supportingmedical equipment M is articulated by the articulation β11. The holder17 has a holding part 17 a to hold the medical equipment M. Accordingly,the medical equipment M is rotatable in every direction under a heldstate. The articulations β10 and β11 have electromagnetic clutches C4and C5, respectively, to lock the rotational position of the medicalequipment M. The principal axis of rotation of articulations β10 and β11are set to have intersection point. Furthermore, the intersection pointis set to agree with the gravitational center of the medical equipmentM. According to the present invention, the shapes of the rotary arm 16and holder 17 are optional, provided that the intersection of thearticulations β10 and β11 agrees with the gravitational center of themedical equipment M. An angle of the principal axis of the articulationβ11 and that of the articulation β10 about the intersection A can be setother than normal.

[0033] The stand apparatus 1 according to the embodiment realizesadditional weight balance about the principal axis of rotation of thearticulation α1. More precisely, opposing parts on each side of theprincipal axis of rotation α1 show weight balance. The stand apparatus 1can be symbolized as a mass concentration distribution in a virtualcylindrical space. The cylindrical space has the center axis α1 and canbe assumed to comprise plurality of pairs of opposing small spaces withrespect to the center axis. If the center axis α1 inclines by an angle θfrom a vertical line, a gravity component Δg=g·sin θ (g being agravitational acceleration) acts in each small space in a directionorthogonal to the center axis α1. In this case, if the gravitationalcenter of one pair of opposing small spaces is on the center axis α1, notorque about the axis α1 occurs regarding the pair of opposing smallspaces. And if the gravitational center of each pair of opposing smallspaces is on the center axis α1, weight balance will be established inthe cylindrical space around the center axis α1. In this condition, evenif the center axis α1 inclines, an object (the stand apparatus) in thevirtual cylindrical space causes no rotation around the axis α1.

[0034] Even if the table 8 to which the stand apparatus 1 is fixed isinclined, the link mechanism 6 will not spontaneously rotate around thearticulation α1 even if the clutch C1 is released. At the same time, thestand apparatus 1 can easily be turned around the articulation α1. Evenif the table 8 is inclined, there is no need of carrying out troublesomehorizontal adjustment.

[0035] Mechanical operation of the stand apparatus 1 will be explainedwith reference to FIGS. 4 to 7. A first characteristic of the standapparatus 1 is to hold the medical equipment M at an optional spatialposition. When the stand apparatus 1 is manipulated to move the medicalapparatus M upward and downward (FIGS. 4 and 5), or to and away from thearticulation S (FIGS. 6 and 7), the weight of the link mechanism 6,support arm 4 a, clutches C1 to C5, medical equipment M, etc., iscancelled by the counterweight W. Therefore the medical equipment M cankeep its center of mass at an optional spatial position even if theclutches C2 and C3 are released without assist of any actuator. Thiswill be explained in detail. A vertical change in the posture (position)of the support arm 4 a shown in FIGS. 4 and 5 is approximated by fixingthe posture (position) of the link mechanism 6, by using thearticulation β1 as an imaginary axis of rotation, and by imaginarysupporting the counterweight W at the articulation β2. Even if thesupport arm 4 a is vertically moved, weight balance around the imaginaryaxis β1 is maintained. In FIG. 6, the posture of the support arm 4 ashown in FIG. 5 is maintained and the inclination angle of the linkmechanism 6 is changed. In this case, the link mechanism 6 maintainsweight balance between the medical equipment M, etc., and thecounterweight W about the articulation S. By combining the vertical andhorizontal posture changes mentioned above, the medical equipment M maybe moved to an optional spatial position as shown in FIG. 7 withoutbreaking weight balance. At any position of the medical equipment M,weight balance about the principal axis of rotation of the articulationα1 is also maintained according to the embodiment.

[0036] A second characteristic of the stand apparatus 1 is to alwaysmaintain a given position/posture of the end link 12 through acombination of the auxiliary parallel link mechanism made of thearticulations S, β1, β6, and β8 and the auxiliary parallel linkmechanism made of the articulations β1, β5, β9, and β7. These twoauxiliary link mechanisms are connected to each other through the crank13, to always maintain a fixed relationship between the orientation of astraight line between the articulations S and β8 and the orientation ofa straight line between the articulations β5 and β9 due to theircooperative linkage. The positions of the articulations S and β8 arefixed on the rotatable member 11 in order to always maintain a fixedposture of the end link 12.

[0037] When the support arm 4 a is vertically moved around thearticulation β1, or when the link mechanism 6 is inclined around thearticulation S to horizontally move the medical equipment M with respectto the table 8 as shown in FIGS. 4 to 7, the end link 12 alwaysmaintains a given posture. Even if the medical equipment M ishorizontally and vertically moved by deforming the link mechanism 6, theend link 12 always maintains a fixed posture. As a result, the holdingstate of the medical equipment M is unchanged, the end link 12 does notrotate, and the end link 12 does not interfere with the head of anoperator while the stand apparatus is being handled.

[0038] A third characteristic of the stand apparatus 1 is to cause nospontaneous rotation of the medical equipment M about the articulationsβ10 and β11. This is realized by intersecting of the articulations β10and β11 and setting the intersection A at the gravitational center ofthe medical equipment M. When the clutches C4 and C5 are released, themedical equipment M is freely rotatably in every direction and is keptbalanced. As a result, auto regulation of posture of the medicalequipment M is achieved by linkage of the auxiliary parallel linkmechanisms and by the agreement of the intersection A of thearticulations β10 and β11 and the gravitational center of the medicalequipment M besides of weight balances about the articulation S and thearticulation α1. Therefore assist-less manipulation of stand apparatusfor keeping the medical equipment M at optional spatial position ormoving it thereto.

[0039] With these three characteristics, the stand apparatus 1 iscapable of simultaneously changing the position/posture of the medicalequipment M by releasing the clutches C1 to C5 and maintaining thechanged position or posture. This is like establishing a gravity-freespace around the medical equipment M and floating the medical equipmentM in the space according to the weight balances. Any optionalposition/posture of the stand apparatus 1 is a kind of unstable balancedposition. Therefore, the medical equipment M supported by the standapparatus 1 is capable of adjusting its position and posture in responseto even a fine motion of an operator or a patient.

[0040] An embodiment applicable to an actual medical scene will beexplained. FIG. 2 shows a cancer reappearance preventive photonradiation system serving as the medical equipment M. The photonradiation system is supported by the stand apparatus 1 and is weaklylinked to a patient, so that a photon radiation position may follow atarget part of the patient in response to even a fine motion such as abreathing motion of the patient. As a result, the photon radiationsystem may effectively work to surely prevent the reappearance ofcancer.

[0041]FIG. 8 shows an endoscope serving as medical equipment M′supported by the stand apparatus 1. The stand apparatus 1 is providedwith a holder 17′ having a holding part 28 to hold the medical equipmentM′. The holding part 28 has opposing V shapes and a knob 29, which isturned to hold and release the endoscope. According to prior arts, anoperator must hold an endoscope, insert a front end of the endoscopeinto the respiratory tract or esophagus of a patient, and manipulate anactuator to operate a target part. In this case, the operator must holdthe endoscope for a long time with one hand and control the front end ofthe endoscope with the other hand. This puts heavy burden on theoperator and requires the operator to have skills. On the contrary, thestand apparatus 1 of the embodiment holds, for the operator, theendoscope and moves like the limbs of the operator. Accordingly, theoperator can concentrate on controlling the front end of the endoscopein the respiratory tract or esophagus of the patient and operate atarget part with the use of the actuator. In this way, the standapparatus 1 of the embodiment serves as a powerful helper to relieve aburden from the operator and shorten an operation time.

Second Embodiment

[0042]FIGS. 9 and 10 show a stand apparatus 18 according to the secondembodiment of the present invention. A counterweight W of the standapparatus 18 is close to the floor F. Like parts are represented withlike reference numerals in the first and second embodiments and theirexplanations will not be repeated.

[0043] The stand apparatus 18 has a base 19 provided with casters 20having a locking mechanism (not shown). When the locking mechanism isreleased, the base 19 with the casters 20 can move on the floor F. Thebase 19 has a post 21 that is rotatable about a vertical axis ofrotation α1. The base 19 and post 21 form a support base. The post 21 isprovided with an electromagnetic clutch C6 to lock the rotation of thepost 21.

[0044] The post 21 has upper and lower articulations S1 and S2. Thelower articulation S2 is offset from just below the upper articulationS1 toward the medical equipment M side. A parallel link mechanism 6 isarticulated at a principal axis of rotation β4 as the same as that ofthe upper articulation S1. An upper end of an interlocked longitudinallink 22 is articulated about a principal axis of rotation S2. When themain axes of a link 2 and the post 21 are substantially agree with eachother as shown in FIG. 9, the upper articulation S1 is offset from anextension of a straight line between the lower articulation S2 and aconnecting articulation β14.

[0045] At the upper articulation S1, the post 21 has a first upperprotrusion 30. A straight line between the upper articulation S1 and anarticulation β8 on the first upper protrusion 30 is equal in length toand parallel with a straight line between a articulation β1 and ahorizontal articulation β6 on a horizontal part of a crank 13. Thearticulation β8 at a front end of the first upper protrusion 30 isconnected to the articulation β6 of the crank 13 through a longitudinalsub-link 14 that is parallel with the link 2.

[0046] In FIG. 9, a lower end of the link 2 has a horizontallyprotruding second upper protrusion 2 a. An upper end of the link 22 hasa lower protrusion 22 a that is equal in length to and parallel with thesecond upper protrusion 2 a. Namely, the length and orientation of astraight line between the upper articulation S1 and a articulation β12on the protrusion 2 a are equal to those of a straight line between thelower articulation S2 and a articulation β13 of the link 22. Thearticulation β12 at the front end of the protrusion 2 a is connected tothe articulation β13 at the front end of the protrusion 22 a through aninterlocked longitudinal sub-link 24 that is parallel with a straightline L1 between the upper articulation S1 and the lower articulation S2.The upper articulation S1, articulations β12 and β13, and lowerarticulation S2 form a first auxiliary parallel link mechanism to alwaysmaintain the posture of the link 22 to be parallel with the posture ofthe link 2.

[0047] An articulation β3 of a lower lateral link 5 of the linkmechanism 6 opposite the medical equipment M is connected to anarticulation β15 of an interlocked lateral link 23 through a weight link25. The weight link 25 is parallel with a straight line L2 extendingbetween the upper articulation S1 and a articulation β14 at a lower endof the link 22. The articulations β14, β15, β3, and β4 form an imaginarysecond auxiliary parallel link mechanism to substantially equalize theposture (position) of the link 23 with that of the link 5. Namely, thelinks 23 and 5 are parallel with each other.

[0048] The articulation β15 is provided with the counterweight W thatacts on the articulation β3 of the link mechanism 6 through the weightlink 25. The lower articulation S2 is provided with an electromagneticclutch C7, and the articulation β14 of the link 22 with anelectromagnetic clutch C8. The clutch C7 locks a motion related to thesub-link 24, and the clutch C8 locks a motion related to the weight link25.

[0049] Mechanical operation of the stand apparatus 18 will be explained.In FIG. 10, the medical equipment M is horizontally moved in anX-direction indicated with an arrow mark. This movement inclines thelink 2 and slightly lifts a support arm 4 a. If only the link 2 isinclined without raising the support arm 4 a, the articulation β1 willgo down to lower the medical equipment M. This is not preferable. Thefirst auxiliary parallel link causes interlocked movements of A0, A1,and A2 indicated with dotted arrow marks. As a result, the link 22inclines with the link 2. Further, the imaginary second auxiliaryparallel link causes interlocked movements of B1 and B2 to move thecounterweight W toward the lower articulation S2. Namely, if theposition of the medical equipment M is changed around the upperarticulation S1, the counterweight W is moved to or away from the lowerarticulation S2 accordingly. The counterweight W acts on thearticulation β3 through the weight link 25, thereby canceling weightacting in the inclining direction of the link mechanism 6. Then, likethe first embodiment, the stand apparatus 18 of the second embodimentkeeps the medical equipment M at an optional spatial position.Substantially no external force is needed to move the medical equipmentM according to the second embodiment, and therefore, one can move themedical equipment M as if it is in a gravity-free state.

[0050] The second embodiment arranges the counterweight W at a lowerposition close to the lower articulation S2 for stabilizing the standapparatus 18. The post 21 has an externally inserted cylinder 27 and anarm 26 attached to the cylinder 27. The arm 26 is fixed to a patienttable 8, so that the stand apparatus 18 may support heavier medicalequipment.

[0051] According to this embodiment, the counterweight W is supported ata location away from the upper articulation S1. In spite of this, thecounterweight W will not widely move when the link 2 is inclined. Inaddition, the position of the articulation β14 is corrected by the link22 in response to the inclination of the link 2. This results ingenerating the motion B2 mentioned above, to correct the position of thesupport arm 4 a.

[0052] In this way, the movement of the counterweight W is small andoccurs in the vicinity of the post 21 due to the offset of the lowerarticulation S2. Accordingly, the stand apparatus 18 of the secondembodiment can be installed in a narrow space. According to the secondembodiment, the base 19 is set on the floor. Instead, the standapparatus of the second embodiment may employ a base (not shown) to beattached to an edge of the patient table 8.

[0053] Although the embodiments have been explained in connection with,as examples of light-weight medical equipment, the photon radiationsystem, endoscope, measuring device, etc., the present invention is notlimited to these examples. For example, the present invention mayhandle, as light-weight medical equipment, a surgical microscope. Thereare many light-weight surgical microscopes that are small orweigh-reduced by removing accessories such as assistant mirrors andvideo cameras. These surgical microscopes are supportable by the standapparatus of the present invention.

[0054] As mentioned above, the medical stand apparatus according to thefirst embodiment employs a base positioned away from the floor, ahorizontally rotatable member, and a protrusion, to directly attach, toa patient table, a parallel link mechanism that includes longitudinaland lateral sub-links to support medical equipment. This stand apparatusneeds no installation space on the floor and is appropriate to supportlight-weight medical equipment.

[0055] The medical stand apparatus according to the second embodimentemploys a base arranged on the floor, a post, a first upper protrusion,a second upper protrusion, a lower protrusion, an interlockedlongitudinal sub-link, and a weight link. With these elements, thesecond embodiment installs, in a narrow space, a parallel link mechanismincluding longitudinal and lateral sub-links to support medicalequipment. The stand apparatus of the second embodiment needs no largespace required by conventional stand apparatuses and is appropriate tosupport light-weight medical equipment.

[0056] The present disclosure relates to subject matter contained inJapanese Patent Applications No. 2000-289074, filed on Sep. 22, 2000,and No. 2001-275721, filed on Sep. 11, 2001, the disclosure of which isexpressly incorporated herein by reference in its entirety.

What is claimed is:
 1. A medical stand apparatus comprising: a basefixed to a patient table at a position away from the floor; ahorizontally rotatable member attached to the base, the horizontallyrotatable member being articulated about a predetermined axis ofrotation; a parallel link mechanism made of a combination of a pair ofparallel longitudinal links and a pair of lateral links, the parallellink mechanism being supported by a first articulation arranged on thehorizontally rotatable member; a support arm extending from the upperlateral link of the parallel link mechanism, a front end of the supportarm supporting an end link whose lower end supports a medical equipment;a counterweight opposite the medical equipment across the firstarticulation, the counterweight canceling weight acting in an incliningdirection of the parallel link mechanism about the articulation andkeeping the medical equipment at an optional spatial position; a crankarticulated about second articulation of the parallel link mechanism,the second articulation serving as a start point of the support arm; alongitudinal sub-link parallel with the longitudinal links, a lower endof the longitudinal sub-link being articulated at a front end of aprotrusion formed on the horizontally rotatable member, one of thelongitudinal links adjacent to the support arm, the crank, thelongitudinal sub-link, and the protrusion forming a first auxiliaryparallel link mechanism; and a lateral sub-link parallel with thesupport arm and connected to the longitudinal sub-link through thecrank, an upper end of the end link being articulated at an end of thelateral sub-link opposite the crank, the support arm, the upper end ofthe end link, the lateral sub-link, and the crank forming a secondauxiliary parallel link mechanism.
 2. A medical stand apparatuscomprising: a base set on the floor, the base having a post installed onthe base, the post being horizontally articulated about an axis ofrotation oriented in a predetermined direction with respect to the base,the post being provided with upper and lower articulations; a parallellink mechanism supported by the upper articulation, the parallel linkhaving a pair of parallel longitudinal links and a pair of laterallinks; a support arm extending from the upper lateral link of theparallel link mechanism, a front end of the support arm supporting anend link; a crank articulated about a first articulation of the parallellink mechanism, the first articulation serving as a start point of thesupport arm; a longitudinal sub-link parallel with the longitudinallinks, a lower end of the longitudinal sub-link being articulated at afront end of a horizontal first upper protrusion formed on the post, oneof the longitudinal links adjacent to the support arm, the crank, thelongitudinal sub-link, and the first upper protrusion forming a firstauxiliary parallel link; a lateral sub-link parallel with the supportarm, the lateral sub-link cooperatively moving in response to positionof the longitudinal sub-link through the crank, an upper end of the endlink being articulated at a first end of the lateral sub-link oppositethe crank, the support arm, the upper end of the end link, the lateralsub-link, and the crank forming a second auxiliary parallel link; aninterlocked longitudinal link always parallel with the longitudinallinks, an upper end of the interlocked longitudinal link beingarticulated at the lower articulation, a lower end of the interlockedlongitudinal link being articulated at a first end of an interlockedlateral link; a second upper protrusion formed at a lower end of thelongitudinal links, a front end of the second upper protrusion beingconnected to a front end of a lower protrusion formed at an upper end ofthe interlocked longitudinal link through an interlocked longitudinalsub-link, the orientation and length of a straight line between upperand lower articulations of the interlocked longitudinal sub-link beingequal to those of a straight line between the upper and lowerarticulations; a weight link connecting an end of the lower lateral linkof the parallel link mechanism opposite the medical equipment and asecond end of the interlocked lateral link, the weight link beingparallel with a straight line between the upper articulation and thefirst end of the interlocked lateral link; and a counterweight arrangedat the second end of the interlocked lateral link, the counterweightcooperatively moving toward and away from the lower articulation inresponse to movement of the medical equipment about the upperarticulation, the weight of the counterweight acting on the parallellink mechanism to keep the medical equipment at an optional spatialposition.
 3. The medical stand apparatus of claim 2, wherein the lowerarticulation is offset from just below the upper articulation toward themedical equipment.
 4. The medical stand apparatus of claims 1 or 2,wherein: a rotary arm is articulated at a third articulation formed atthe end link, the rotary arm having a forth articulation, a holder tohold the medical equipment being articulated at the forth articulation,each principal axis of rotation of the third articulation and the fortharticulation intersecting; and the intersection is set to agree with thegravitational center of the medical equipment.
 5. The medical standapparatus of 4 wherein each principal axis of rotation of the thirdarticulation and the fourth articulation are substantially orthogonal toeach other.
 6. An assist-less medical stand apparatus for manipulating amedical equipment used for a patient on a patient table comprising: afirst parallel linkage for weight balancing of the apparatus having afirst articulating element, a second articulating element, a thirdarticulating element, and a fourth articulating element, the firstarticulating element and the second articulating element being linked bya first linkage, the second articulating element and the thirdarticulating element being linked by a second linkage, the thirdarticulating element and the fourth articulating element being linked bya third linkage, the fourth articulating element and the firstarticulating element being linked by a fourth linkage, the thirdarticulating element supporting a counterweight, the first linkage beingarticulated by a fifth articulating element on a supporting member, andthe supporting member fixing the apparatus with respect to the patienttable; a second parallel linkage having a sixth articulating element, aseventh articulating element, a eighth articulating element, and a nintharticulating element, the sixth articulating element and the seventharticulating element being linked by a sixth linkage, the seventharticulating element and the eighth articulating element being linked bya seventh linkage, the eighth articulating element and the nintharticulating element being linked by a eighth linkage, the nintharticulating element and the sixth articulating element being linked bya fifth linkage, the sixth linkage being fixed with respect to thesupporting member, and the fifth linkage and the first linkage beingfixed each other; and a third parallel linkage to cooperatively movewith the second parallel linkage for holding the medical equipment andkeeping a position thereof having a tenth articulating element, aneleventh articulating element, a twelfth articulating element, and athirteenth articulating element, the tenth articulating element and theeleventh articulating element being linked by a ninth linkage, theeleventh articulating element and the twelfth articulating element beinglinked by a tenth linkage, the twelfth articulating element and thethirteenth articulating element being linked by a eleventh linkage, thethirteenth articulating element and the tenth articulating element beinglinked by a twelfth linkage, the thirteenth articulating element beingfixed by the fourth linkage, the tenth articulating element, the nintharticulating element, and the first articulating element being fixedeach other, and the eleventh articulating element and the eightharticulating element being linked by a thirteenth linkage.
 7. Anassist-less medical stand apparatus for manipulating a medical equipmentused for a patient on a patient table comprising: a first articulationpositioned at a first end of a first link; a second articulationpositioned at a second end of the first link, the second articulationbeing arranged at a predetermined position on a base; a thirdarticulation positioned at a first end of a second link; a fourtharticulation positioned at a second end of the second link, the firstarticulation, the third articulation, the fourth articulation, and thesecond articulation forming a first parallel link mechanism; a fiftharticulation positioned at a first end of a third link at apredetermined position with respect to the base; a sixth articulationpositioned at a second end of the third link, the first articulation,the sixth articulation, the fifth articulation, and the secondarticulation forming a second parallel link mechanism; a seventharticulation positioned at a front end of a support arm extending fromthe first articulation; an eighth articulation positioned at a first endof a fourth link; a ninth articulation positioned at a second end of thefourth link, the eighth articulation and the ninth articulation beinglinked by an end link for holding the medical equipment and keeping aposition thereof, the eighth articulation, the ninth articulation, theseventh articulation, and the first articulation forming a thirdparallel link mechanism; a tenth articulation positioned below thesecond articulation on the base; an eleventh articulation positioned ata first end of a fifth link; a twelfth articulation positioned at asecond end of the fifth link, and the second articulation, the eleventharticulation, the twelfth articulation, and the tenth articulationforming a fourth parallel link mechanism; a thirteenth articulationpositioned at a first end of a sixth link and supporting acounterweight, and a second end of the sixth link being articulated onthe fourth articulation; and a fourteenth articulation positioned at afirst end of a seventh link, a second end of the seventh link beingarticulated on the thirteenth articulation, wherein: the third andsecond parallel link mechanisms cooperate with each other through alinkage between the sixth and eighth articulations; and the tenth andfourteenth articulations are linked with an eighth link which cooperateswith the fourth parallel link mechanism.
 8. The apparatus of claims 6,wherein: the supporting member is attached to the patient table; thesupporting member has a fourteenth articulating element; the fiftharticulating element is articulated about an axis of rotation of thefourteenth articulating element; and weight balancing is realized aboutan axis of rotation of the fourteenth articulating element.
 9. Theapparatus of claim 7, wherein the tenth articulation is offset from justbelow the second articulation toward the medical equipment.
 10. Theapparatus of claim 7 wherein the base is set on the floor.
 11. Theapparatus of claim 6, further comprising: a thirteenth articulatingelement fixed to the eleventh linkage; and a rotary arm for holding themedical equipment articulated by the thirteenth articulating element,the rotary arm having a holder articulated thereon by a fourteentharticulating element, principal axis of rotation of the thirteentharticulating element and that of the fourteenth articulating elementintersecting, and the intersection being set to agree with thegravitational center of the medical equipment.
 12. The apparatus ofclaim 7, further comprising a rotary arm articulated on the end linkabout a first principal axis of rotation, the rotary arm having a holderarticulated on the rotary arm about a second principal axis of rotation,the first principal axis of rotation and the second principal axis ofrotation intersecting, and the intersection being set to agree with thegravitational center of the medical equipment.
 13. The apparatus ofclaim 11 wherein principal axis of rotation of the thirteentharticulation element and that of the fourteenth articulation element aresubstantially orthogonal to each other.
 14. The apparatus of claim 12wherein the first principal axis of rotation and the second principalaxis of rotation are substantially orthogonal to each other.